1. Field of the Invention
The invention is directed to an improved threaded pipe coupling, comprising a connection stub, a pipe with a nipple, and a union nut.
2. Description of the Prior Art
Threaded pipe couplings have long been known in the prior art, and are used for instance in the high-pressure region of fuel injection systems for internal combustion engines. A threaded coupling of this kind may for instance be provided on both ends of a high-pressure line that is mounted between a common rail and an injector.
In some internal combustion engines, the problem arises that the injectors are located entirely inside the cylinder head cap of the engine. This means that only the high-pressure line is passed through the cylinder head cap. As a consequence, any leakages that occur at the threaded pipe coupling between the high-pressure line and the injector dilute and thin the motor oil which can cause engine damage. In rare cases, but these cannot be precluded, it is even possible for the leakages to get into the intake tube via the venting of the valve drive and thus can get into the combustion chambers of the engine. This can lead to dangerous situations.